// Warp an image and return a new Bitmap32 holding the result.
public Bitmap32 Warp(WarpOperations warp_op, bool lock_result)
{
// Make a copy of this Bitmap32.
Bitmap32 result = this.Clone();
// Lock both bitmaps.
bool was_locked = this.IsLocked;
this.LockBitmap();
result.LockBitmap();
// Warp the image.
WarpImage(this, result, warp_op);
// Unlock the bitmaps.
if (!lock_result)
{
result.UnlockBitmap();
}
if (!was_locked)
{
this.UnlockBitmap();
}
// Return the result.
return(result);
}
private static void WarpImage(Warping bm_src, Warping bm_dest, WarpOperations warp_op)
{
double xmid = bm_dest.Width / 2.0;
double ymid = bm_dest.Height / 2.0;
double rmax = bm_dest.Width * 0.75;
int ix_max = bm_src.Width - 2;
int iy_max = bm_src.Height - 2;
double x0, y0;
for (int y1 = 0; y1 < bm_dest.Height; y1++)
{
for (int x1 = 0; x1 < bm_dest.Width; x1++)
{
MapPixel(warp_op, xmid, ymid, rmax, x1, y1, out x0, out y0);
int ix0 = (int)x0;
int iy0 = (int)y0;
if ((ix0 < 0) || (ix0 > ix_max) ||
(iy0 < 0) || (iy0 > iy_max))
{
bm_dest.SetPixel(x1, y1, 255, 255, 255, 255);
}
else
{
double dx0 = x0 - ix0;
double dy0 = y0 - iy0;
double dx1 = 1 - dx0;
double dy1 = 1 - dy0;
byte r00, g00, b00, a00, r01, g01, b01, a01,
r10, g10, b10, a10, r11, g11, b11, a11;
bm_src.GetPixel(ix0, iy0, out r00, out g00, out b00, out a00);
bm_src.GetPixel(ix0, iy0 + 1, out r01, out g01, out b01, out a01);
bm_src.GetPixel(ix0 + 1, iy0, out r10, out g10, out b10, out a10);
bm_src.GetPixel(ix0 + 1, iy0 + 1, out r11, out g11, out b11, out a11);
int r = (int)(
r00 * dx1 * dy1 + r01 * dx1 * dy0 +
r10 * dx0 * dy1 + r11 * dx0 * dy0);
int g = (int)(
g00 * dx1 * dy1 + g01 * dx1 * dy0 +
g10 * dx0 * dy1 + g11 * dx0 * dy0);
int b = (int)(
b00 * dx1 * dy1 + b01 * dx1 * dy0 +
b10 * dx0 * dy1 + b11 * dx0 * dy0);
int a = (int)(
a00 * dx1 * dy1 + a01 * dx1 * dy0 +
a10 * dx0 * dy1 + a11 * dx0 * dy0);
bm_dest.SetPixel(x1, y1, (byte)r, (byte)g, (byte)b, (byte)a);
}
}
}
}
public Warping Warp(WarpOperations warp_op, bool lock_result)
{
Warping result = this.Clone();
bool was_locked = this.IsLocked;
this.LockBitmap();
result.LockBitmap();
WarpImage(this, result, warp_op);
if (!lock_result)
{
result.UnlockBitmap();
}
if (!was_locked)
{
this.UnlockBitmap();
}
return(result);
}
// Map the output pixel (x1, y1) back to the input pixel (x0, y0).
private static void MapPixel(WarpOperations warp_op, double xmid, double ymid, double rmax, int x1, int y1, out double x0, out double y0)
{
const double pi_over_2 = Math.PI / 2.0;
const double K = 100.0;
const double offset = -pi_over_2;
double dx, dy, r1, r2;
switch (warp_op)
{
case WarpOperations.Identity:
x0 = x1;
y0 = y1;
break;
case WarpOperations.FishEye:
dx = x1 - xmid;
dy = y1 - ymid;
r1 = Math.Sqrt(dx * dx + dy * dy);
if (r1 == 0)
{
x0 = xmid;
y0 = ymid;
}
else
{
r2 = rmax / 2 * (1 / (1 - r1 / rmax) - 1);
x0 = dx * r2 / r1 + xmid;
y0 = dy * r2 / r1 + ymid;
}
break;
case WarpOperations.Twist:
dx = x1 - xmid;
dy = y1 - ymid;
r1 = Math.Sqrt(dx * dx + dy * dy);
if (r1 == 0)
{
x0 = 0;
y0 = 0;
}
else
{
double theta = Math.Atan2(dx, dy) - r1 / K - offset;
x0 = r1 * Math.Cos(theta);
y0 = r1 * Math.Sin(theta);
}
x0 = x0 + xmid;
y0 = y0 + ymid;
break;
case WarpOperations.Wave:
x0 = x1;
y0 = y1 - 10 * (Math.Sin(x1 / 50.0 * Math.PI) + 1) + 5;
break;
case WarpOperations.SmallTop:
dx = xmid - x1;
dx = dx * ymid * 2 / (y1 + 1);
x0 = xmid - dx;
y0 = y1;
break;
case WarpOperations.Wiggles:
dx = xmid - x1;
dx = dx * (Math.Sin(y1 / 50.0 * Math.PI) / 2 + 1.5);
x0 = xmid - dx;
y0 = y1;
break;
case WarpOperations.DoubleWave:
x0 = x1 - 10 * (Math.Sin(y1 / 50.0 * Math.PI) + 1) + 5;
y0 = y1 - 10 * (Math.Sin(x1 / 50.0 * Math.PI) + 1) + 5;
break;
default: // Flip vertically and horizontally.
x0 = 2 * xmid - x1;
y0 = 2 * ymid - y1;
break;
}
}
// Transform the image.
private static void WarpImage(Bitmap32 bm_src, Bitmap32 bm_dest, WarpOperations warp_op)
{
// Calculate some image information.
double xmid = bm_dest.Width / 2.0;
double ymid = bm_dest.Height / 2.0;
double rmax = bm_dest.Width * 0.75;
int ix_max = bm_src.Width - 2;
int iy_max = bm_src.Height - 2;
// Generate a result for each output pixel.
double x0, y0;
for (int y1 = 0; y1 < bm_dest.Height; y1++)
{
for (int x1 = 0; x1 < bm_dest.Width; x1++)
{
// Map back to the source image.
MapPixel(warp_op, xmid, ymid, rmax, x1, y1, out x0, out y0);
// Interpolate to get the result pixel's value.
// Find the next smaller integral position.
int ix0 = (int)x0;
int iy0 = (int)y0;
// See if this is out of bounds.
if ((ix0 < 0) || (ix0 > ix_max) ||
(iy0 < 0) || (iy0 > iy_max))
{
// The point is outside the image. Use white.
bm_dest.SetPixel(x1, y1, 255, 255, 255, 255);
}
else
{
// The point lies within the image.
// Calculate its value.
double dx0 = x0 - ix0;
double dy0 = y0 - iy0;
double dx1 = 1 - dx0;
double dy1 = 1 - dy0;
// Get the colors of the surrounding pixels.
byte r00, g00, b00, a00, r01, g01, b01, a01,
r10, g10, b10, a10, r11, g11, b11, a11;
bm_src.GetPixel(ix0, iy0, out r00, out g00, out b00, out a00);
bm_src.GetPixel(ix0, iy0 + 1, out r01, out g01, out b01, out a01);
bm_src.GetPixel(ix0 + 1, iy0, out r10, out g10, out b10, out a10);
bm_src.GetPixel(ix0 + 1, iy0 + 1, out r11, out g11, out b11, out a11);
// Compute the weighted average.
int r = (int)(
r00 * dx1 * dy1 + r01 * dx1 * dy0 +
r10 * dx0 * dy1 + r11 * dx0 * dy0);
int g = (int)(
g00 * dx1 * dy1 + g01 * dx1 * dy0 +
g10 * dx0 * dy1 + g11 * dx0 * dy0);
int b = (int)(
b00 * dx1 * dy1 + b01 * dx1 * dy0 +
b10 * dx0 * dy1 + b11 * dx0 * dy0);
int a = (int)(
a00 * dx1 * dy1 + a01 * dx1 * dy0 +
a10 * dx0 * dy1 + a11 * dx0 * dy0);
bm_dest.SetPixel(x1, y1, (byte)r, (byte)g, (byte)b, (byte)a);
}
}
}
}
private static void WarpImage(Warping bm_src, Warping bm_dest, WarpOperations warp_op)
{
double xmid = bm_dest.Width / 2.0;
double ymid = bm_dest.Height / 2.0;
double rmax = bm_dest.Width * 0.75;
int ix_max = bm_src.Width - 2;
int iy_max = bm_src.Height - 2;
double x0, y0;
for (int y1 = 0; y1 < bm_dest.Height; y1++)
{
for (int x1 = 0; x1 < bm_dest.Width; x1++)
{
MapPixel(warp_op, xmid, ymid, rmax, x1, y1, out x0, out y0);
int ix0 = (int)x0;
int iy0 = (int)y0;
if ((ix0 < 0) || (ix0 > ix_max) ||
(iy0 < 0) || (iy0 > iy_max))
{
bm_dest.SetPixel(x1, y1, 255, 255, 255, 255);
}
else
{
double dx0 = x0 - ix0;
double dy0 = y0 - iy0;
double dx1 = 1 - dx0;
double dy1 = 1 - dy0;
byte r00, g00, b00, a00, r01, g01, b01, a01,
r10, g10, b10, a10, r11, g11, b11, a11;
bm_src.GetPixel(ix0, iy0, out r00, out g00, out b00, out a00);
bm_src.GetPixel(ix0, iy0 + 1, out r01, out g01, out b01, out a01);
bm_src.GetPixel(ix0 + 1, iy0, out r10, out g10, out b10, out a10);
bm_src.GetPixel(ix0 + 1, iy0 + 1, out r11, out g11, out b11, out a11);
int r = (int)(
r00 * dx1 * dy1 + r01 * dx1 * dy0 +
r10 * dx0 * dy1 + r11 * dx0 * dy0);
int g = (int)(
g00 * dx1 * dy1 + g01 * dx1 * dy0 +
g10 * dx0 * dy1 + g11 * dx0 * dy0);
int b = (int)(
b00 * dx1 * dy1 + b01 * dx1 * dy0 +
b10 * dx0 * dy1 + b11 * dx0 * dy0);
int a = (int)(
a00 * dx1 * dy1 + a01 * dx1 * dy0 +
a10 * dx0 * dy1 + a11 * dx0 * dy0);
bm_dest.SetPixel(x1, y1, (byte)r, (byte)g, (byte)b, (byte)a);
}
}
}
}
private static void MapPixel(WarpOperations warp_op, double xmid, double ymid, double rmax, int x1, int y1, out double x0, out double y0)
{
const double pi_over_2 = Math.PI / 2.0;
const double K = 100.0;
const double offset = -pi_over_2;
double dx, dy, r1, r2;
switch (warp_op)
{
case WarpOperations.Identity:
x0 = x1;
y0 = y1;
break;
case WarpOperations.FishEye:
dx = x1 - xmid;
dy = y1 - ymid;
r1 = Math.Sqrt(dx * dx + dy * dy);
if (r1 == 0)
{
x0 = xmid;
y0 = ymid;
}
else
{
r2 = rmax / 2 * (1 / (1 - r1 / rmax) - 1);
x0 = dx * r2 / r1 + xmid;
y0 = dy * r2 / r1 + ymid;
}
break;
case WarpOperations.Twist:
dx = x1 - xmid;
dy = y1 - ymid;
r1 = Math.Sqrt(dx * dx + dy * dy);
if (r1 == 0)
{
x0 = 0;
y0 = 0;
}
else
{
double theta = Math.Atan2(dx, dy) - r1 / K - offset;
x0 = r1 * Math.Cos(theta);
y0 = r1 * Math.Sin(theta);
}
x0 = x0 + xmid;
y0 = y0 + ymid;
break;
case WarpOperations.Wave:
x0 = x1;
y0 = y1 - 10 * (Math.Sin(x1 / 50.0 * Math.PI) + 1) + 5;
break;
case WarpOperations.SmallTop:
dx = xmid - x1;
dx = dx * ymid * 2 / (y1 + 1);
x0 = xmid - dx;
y0 = y1;
break;
case WarpOperations.Wiggles:
dx = xmid - x1;
dx = dx * (Math.Sin(y1 / 50.0 * Math.PI) / 2 + 1.5);
x0 = xmid - dx;
y0 = y1;
break;
case WarpOperations.DoubleWave:
x0 = x1 - 10 * (Math.Sin(y1 / 50.0 * Math.PI) + 1) + 5;
y0 = y1 - 10 * (Math.Sin(x1 / 50.0 * Math.PI) + 1) + 5;
break;
default:
x0 = 2 * xmid - x1;
y0 = 2 * ymid - y1;
break;
}
}
public Warping Warp(WarpOperations warp_op, bool lock_result)
{
Warping result = this.Clone();
bool was_locked = this.IsLocked;
this.LockBitmap();
result.LockBitmap();
WarpImage(this, result, warp_op);
if (!lock_result) result.UnlockBitmap();
if (!was_locked) this.UnlockBitmap();
return result;
}
